A trend in the firearms field has been to move away from purely mechanical firearm sights (such as iron sights) and move towards electronic reflex-type (or red dot) firearm sights which offer no magnification. These types of firearm sights, while generally robust, may fail to reliably function on a regular basis and therefore must be supplemented by back-up iron sight assemblies that allow a user to “flip” up the iron sights into the sighting plane when the electronic firearm sights fail. The user is able to sight the firearm by viewing the front sight of the firearm through the non-functional electronic sight and aligning it with the aperture or other sighting mechanism on the rear backup sight. This system, while marginally effective with the previous generation of non-magnified electronic or optical firearm sights, has, in certain instances, been rendered unusable on the new generation of magnified optical sight devices. One reason for this is that the fixed front sight of the firearm cannot be viewed through the restricted view of a magnified sight device.